Gardeners always seem to have plenty of questions.

QI have a black gum tree in my front yard that is putting out more suckers than usual this year. They sprout up all over the lawn around the tree. I tried to pull them, but the base of the sucker remains firmly in the ground. I found a product called Sucker Stopper RTU but don't know if it's the right product to use. Mowing only seems to make them stronger. -- Chelsea Sutula

AThese suckers, also called water sprouts, grow from roots, other branches or the base of a tree and should be removed. The best sucker control is to grab and tear each one from the tree while it's still a young, green stem. Pruning like this can be a big job. When they are sprouting from the root zone, mowing is probably the easiest way to keep them at bay -- two to three inches in height with less possibility of returning next year.

A growth retardant is sometimes used on young green stems. It will keep suckers from forming on some trees and lasts for about three months. The chemical is Napthaleneacetate (NAA), sold under the name Sucker Stopper RTU made by Monterey Lawn and Garden. Contact the manufacturer to be sure it is approved for black gum suckers. Always use chemicals according to labeled instructions.

Recently I saw an article about a woman who planted thimbleberry on a red cedar trunk and it looked terrific. What do you think about that idea? -- Camille Cook

Thimbleberry (Rubus odoratus), a thornless flowering raspberry, is an erect-growing, shrubby native plant that blooms all summer and can be trained up a dead tree trunk to create a flowering wildlife habitat. It produces a tasteless fruit. Leaving dead tree trunks standing five to 10 feet tall and training climbing plants on them for ornamental value is an excellent landscape design idea.

We are building a house. The existing house on the lot is to be burned down by the fire department. In the process, they are clearing most of the original vegetation. There are some azaleas and rose bushes we are going to dig and keep. Is it okay to cut them back before digging at this time of year? -- Terry Forche

Transplanting established old shrubs at this time of year tests a plant's vim and vigor. If the roses and azaleas have to be moved now to accommodate building, move them. Here is one way to move the roses:

Cut to 10 inches in height and dig. Instead of digging root balls, carefully expose all the wiry roots using a potato fork. (It looks like a small, short-handled pitchfork with wide, flat tines.) After capturing most of the roots intact, wrap them in wet burlap to take to the new location. Plant the roses in soil mixed with composted manure and water each one. You might lose some.

To transplant azaleas, cut them to 18 to 24 inches tall. This might sacrifice one year of flowers. Dig a ball that is commensurate with the thickness of the azalea trunks. Old plants could require a root ball as wide as 18 to 24 inches and 12 inches deep. Each could weigh 200 pounds or more. Because you are doing demolition, you don't have to carefully hand-dig them. Use a backhoe. The bucket of a medium size (18 to 24 inches) scoop will lift about the right-size soil ball. The soil should be moist, not soggy. Use burlap to keep the soil on the roots when moving them. Replant in soil that's rich in compost. Keep plants evenly moist during their first growing season in the new location.

Do not fertilize newly transplanted shrubs. However, all newly planted flora benefit greatly from the addition of growth stimulants, such as plant vitamins like SUPERthrive, kelp- and fish-based nutrients like Bio-Plex or Coast of Maine Fermented Salmon, and humic acid-based materials like Roots.

We live in a small community that has three traffic circles, each about 38 feet in diameter. We would like to spruce up these circles with a small tree, bushes and perhaps some perennials. We don't have a way to water them and they would get full sun. -- Wayne Minger

During the first year of installation, all plants need management and care, including water. Once established, the plantings suggested will require very little maintenance -- some weeding, mulching, pruning, deadheading and minimal water.

To determine the best plants for your community, you need to answer the following questions: What flowering trees are growing in the community now? Do you want formal or natural? Is color coordination more desirable than all evergreen? Is deer-browsing a problem? What's the circulation pattern around the circles? (Never block the line of sight that keeps a driver from seeing another car or pedestrian approaching.)

Large rock outcroppings and an asymmetrical arrangement of perennials create a natural theme. Drought-tolerant perennials such as black-eyed Susans, echinacea, liatris and coreopsis are a few you might use. Virginia sweetspire shrubs will colonize an area. Bayberries are semi-evergreen and display waxy, gray-white berries through winter. Try a single blue spruce or evergreen holly, or a flowering deciduous tree such as serviceberry (Amelanchier), stewartia, crape myrtle or a tall-growing crab apple in each circle for a vertical element.

Accomplish more formality with symmetry and strong repetition. Consider low junipers as a ground cover and groupings of rugosa roses for summer color and winter texture. A blue spruce would be a good conifer to complement the other plants. A tough deciduous tree instead of a spruce could be lacebark elm (Ulmus parvifolia), goldenrain tree (Koelreuteria paniculata) or crape myrtle.

I had a kousa dogwood planted about five years ago. It was full of blossoms at the time. For four years in a row it has grown taller and wider but has not had a single blossom. It appears very healthy and each year I wait for blossoms, but have not had one. Could you give me some ideas, please? -- Charlotte Greene

Kousa dogwood is one that will tolerate more sun than other dogwoods. It is a good ornamental tree with a long flowering period, lacy bark, maroon fall foliage and red fruit that persists into late fall. You are describing a healthy specimen -- except for the lack of flowers and fruit. The number one reason that healthy plants don't flower is because they are growing in too much shade. If you can thin trees that are shading it or determine another way to get more sun to the tree, it will begin flowering again. Dogwoods bloom on last year's wood. Therefore, it will take a full growing season with more sun before you reap flowering rewards from this tree.

I have a doublefile viburnum planted four to five years ago. The planting site isn't big enough and I must frequently prune the shrub to keep it in bounds, destroying its shape. It's about 7 feet tall and wide. Is it possible to move my shrub? How and when should this be done? -- Linda Bruner

Your viburnum (V. plicatum var. tomentosum) is one of the most beautiful in bloom, with flat flowers lining its horizontal branching stems in spring, berries attracting birds in summer and reddish-purple fall leaf color. It's a fibrous-rooted shrub that is rather easy to transplant. Because of the branching habit you might want to tie the stems up to dig the root ball. Root-prune it now by slicing down around the root ball, and to stimulate tight root growth. Transplant by digging outside the roots you pruned late next winter before any growth has begun.

I was overjoyed to see your advice about deadheading rhododendrons. I have three that bloomed very well last year and this year. They are growing taller. When and how do I prune them, and how much should I prune? -- Sheldon Goldberg

Do corrective pruning now, right after flowering. Cut the stems that are too tall or wide. Cut selectively, following stems down into the plant to cut them at a whorl of leaves on the stem or a crossing branch. Reduce the greenery by one-third without concern.

Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site,

Kousa dogwood tolerates more sun than other dogwoods and it requires a full growing season before it blooms. It also is a good ornamental tree with a long flowering period. Echinacea, left, is a drought-tolerant native perennial that provides tall, pinkish-purple flowers. The threadleaf coreopsis, right, is another drought-tolerant native perennial wildflower.